lwip_max_tcp_pcb.diff

diff --git a/components/lwip/lwip/src/core/memp.c b/components/lwip/lwip/src/core/memp.c
index 352ce5a55127a658b6b3c9d8541298c42df332ff..39433cf476b3456b046e337e9b1f016299964a84 100644
--- a/components/lwip/lwip/src/core/memp.c
+++ b/components/lwip/lwip/src/core/memp.c
@@ -240,6 +240,10 @@ memp_init(void)
 #endif /* MEMP_OVERFLOW_CHECK >= 2 */
 }
 
+#if MEMP_MEM_MALLOC && ESP_LWIP && LWIP_TCP
+static u32_t num_tcp_pcb = 0;
+#endif
+
 static void *
 #if !MEMP_OVERFLOW_CHECK
 do_memp_malloc_pool(const struct memp_desc *desc)
@@ -251,6 +255,16 @@ do_memp_malloc_pool_fn(const struct memp_desc *desc, const char *file, const int
   SYS_ARCH_DECL_PROTECT(old_level);
 
 #if MEMP_MEM_MALLOC
+#if ESP_LWIP
+#if LWIP_TCP
+  if(desc == memp_pools[MEMP_TCP_PCB]){
+    if(num_tcp_pcb >= MEMP_NUM_TCP_PCB){
+        return NULL;
+    }
+  }
+#endif
+#endif
+
   memp = (struct memp *)mem_malloc(MEMP_SIZE + MEMP_ALIGN_SIZE(desc->size));
   SYS_ARCH_PROTECT(old_level);
 #else /* MEMP_MEM_MALLOC */
@@ -260,6 +274,12 @@ do_memp_malloc_pool_fn(const struct memp_desc *desc, const char *file, const int
 #endif /* MEMP_MEM_MALLOC */
 
   if (memp != NULL) {
+#if MEMP_MEM_MALLOC && ESP_LWIP && LWIP_TCP
+  if (desc == memp_pools[MEMP_TCP_PCB]) {
+    num_tcp_pcb++;
+  }
+#endif
+
 #if !MEMP_MEM_MALLOC
 #if MEMP_OVERFLOW_CHECK == 1
     memp_overflow_check_element(memp, desc);
@@ -369,6 +389,12 @@ do_memp_free_pool(const struct memp_desc *desc, void *mem)
 
   SYS_ARCH_PROTECT(old_level);
 
+#if MEMP_MEM_MALLOC && ESP_LWIP && LWIP_TCP
+  if (desc == memp_pools[MEMP_TCP_PCB]) {
+    num_tcp_pcb--;
+  }
+#endif
+
 #if MEMP_OVERFLOW_CHECK == 1
   memp_overflow_check_element(memp, desc);
 #endif /* MEMP_OVERFLOW_CHECK */
diff --git a/components/lwip/lwip/src/core/tcp.c b/components/lwip/lwip/src/core/tcp.c
index 3fbdd89ae07807208ff7466abb50f90b5e7727e4..fe6baaf250927cb4b89f8d1dbd41c73def88692b 100644
--- a/components/lwip/lwip/src/core/tcp.c
+++ b/components/lwip/lwip/src/core/tcp.c
@@ -1765,7 +1765,9 @@ tcp_kill_state(enum tcp_state state)
   struct tcp_pcb *pcb, *inactive;
   u32_t inactivity;
 
+#if !ESP_LWIP
   LWIP_ASSERT("invalid state", (state == CLOSING) || (state == LAST_ACK));
+#endif
 
   inactivity = 0;
   inactive = NULL;
@@ -1870,17 +1872,41 @@ tcp_alloc(u8_t prio)
         tcp_kill_state(CLOSING);
         /* Try to allocate a tcp_pcb again. */
         pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+#if ESP_LWIP
         if (pcb == NULL) {
-          /* Try killing oldest active connection with lower priority than the new one. */
-          LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing oldest connection with prio lower than %d\n", prio));
-          tcp_kill_prio(prio);
-          /* Try to allocate a tcp_pcb again. */
+          /* Try killing oldest connection in FIN_WAIT_2. */
+          LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest FIN_WAIT_2 connection\n"));
+          tcp_kill_state(FIN_WAIT_2);
           pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+          if (pcb == NULL) {
+            /* Try killing oldest connection in FIN_WAIT_1. */
+            LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing off oldest FIN_WAIT_1 connection\n"));
+            tcp_kill_state(FIN_WAIT_1);
+            pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+#endif
+            if (pcb == NULL) {
+              /* Try killing oldest active connection with lower priority than the new one. */
+              LWIP_DEBUGF(TCP_DEBUG, ("tcp_alloc: killing oldest connection with prio lower than %d\n", prio));
+              tcp_kill_prio(prio);
+              /* Try to allocate a tcp_pcb again. */
+              pcb = (struct tcp_pcb *)memp_malloc(MEMP_TCP_PCB);
+              if (pcb != NULL) {
+                /* adjust err stats: memp_malloc failed multiple times before */
+                MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+              }
+            }
+#if ESP_LWIP
+            if (pcb != NULL) {
+            /* adjust err stats: memp_malloc failed multiple times before */
+            MEMP_STATS_DEC(err, MEMP_TCP_PCB);
+            }
+          }
           if (pcb != NULL) {
             /* adjust err stats: memp_malloc failed multiple times before */
             MEMP_STATS_DEC(err, MEMP_TCP_PCB);
           }
         }
+#endif
         if (pcb != NULL) {
           /* adjust err stats: memp_malloc failed multiple times before */
           MEMP_STATS_DEC(err, MEMP_TCP_PCB);